MT_CNT
if (report_size > KEY_CNT + REL_CNT + ABS_CNT + MAX_MT_SLOTS * MT_CNT +
bit_count(evdev->ev_abs_flags, ABS_MT_FIRST, MT_CNT, &res);
int32_t val[MT_CNT];
#define HMT_N_USAGES MT_CNT
#define WMT_N_USAGES MT_CNT